Combined vhf-uhf dipole antenna



April 23, 0 A l. s. BLONDER 3,509,574

COMBINED VHF-UHF DIPOLE ANTENNA Original Filed June 30, 1965 INVENTOR.

' ISAAC S. BLONDER ATTORNEYS United States Patent 3,509,574 COMBINED VHF-UHF DIPOLE ANTENNA Isaac S. Blonder, West Orange, N.J., assignor to Blonder- }ongue Electronics, Newark, N .J., a corporation of New ersey Continuation of application Ser. No. 468,221, June 30,

1965. This application Oct. 1, 1968, Ser. No. 814,469

Int. Cl. H01q 11/10 U.S. Cl. 343792.5 13 Claims ABSTRACT OF THE DISCLOSURE This disclosure deals with a combined VHF and UHF antenna structure employing vertically spaced longitudinal conductor members supporting sets of dipole elements of successively increasing length, the conductor members of the UHF section converging to a feed-point at one end thereof and also feeding the conductor members of the VHF section.

This application is a continuation of Ser. No. 468,221, filed June 30, 1965, and now abandoned for Wide Band Directive Antenna.

The present invention relates to wide band directive antennas and, more particularly, to antennas designed to receive high frequency radio transmissions in both the VHF and UHF television bands; though the invention is useful with other wide frequency band ranges as Well.

When directive radio and television receiving antenna arrays are constructed to extend over very wide bands of frequencies or wavelengths requiring entirely different physical structural elements for receiving the very low and the very high frequencies, it becomes necessary to combine differently dimensioned structures in a single construction in such a manner as to insure minimal deleterious interaction between those structural elements effective to receive certain frequencies and those elements that are not effective receiving elements at such frequencies. This has led to many odd-shaped configurations, compensatory structures and difiicult and costly constructions that have represented a serious compromise in performance.

An object of the invention, accordingly, is to provide a new and improved antenna structure that largely obviates these disadvantages and provides remarkably wide band directive reception patterns in a single, simple structure over, for example, such vast frequency ranges as the complete VHF and UHF bands ranging from about 54 me. up to about 900 mc.a factor of as much as almost 20-to-1.

A further object is to provide a new and improved antenna of more general use also.

Other and further objects will be explained hereinafter, and will be more particularly pointed out in the appended claims.

In summary, the invention contemplates a combination of VHF and UHF structures designed such that reception in all bands is of the desired directivity and gain with minimal deleterious interaction between the VHF and UHF structural portions of the antenna, employing pairs of vertically spaced apart rigid conductors from which dipole elements extend transversely at successive points therealong with the dipole elements connected to one conductor extending in the opposite direction to the corresponding dipole elements of the other conductor of the pair, and with the length of the dipole elements successively increasing from one end of the conductors to the other end. Preferred construction details are hereinafter set forth.

The invention will now be described in connection with the accompanying drawing the single figure of which is an isometric view of a preferred embodiment of the antenna, illustrated for purposes of explanation and example only, as applied to the VHF and UHF television reception problem. Both the VHF and UHF portions of the structure shown in the drawing are of the general type disclosed in my co-pending application, Directive Antenna, Ser. No. 325,511, filed Nov. 21, 1963, now Patent No. 3,259,904, granted July 5, 1966, embodying a pair of vertically spaced apart rigid longitudinal conductors having dipole elements extending therefrom in a transverse plane.

Referring to the VHF portion I, a pair of rigid conductor members is shown at .1 and 1 held spaced apart in a vertical plane, the term vertical as well as the hereinafter employed term horizontal, being intended to be illustrative of relative orientations without being confined to actual direction. The first pair of conductor members 1 and 1' is provided with sets of dipole elements 5, 7, 9, 11 and 5', 7', 9 11, which, in the form shown, lie in corresponding first and second vertically spaced substantially horizontal planes containing the respective longitudinal conductor members 1 and 1'. The pluralities or sets of dipole, elements angularly extend transversely from opposite sides of each conductor member at successive points longitudinally spaced therealong. The dipole elements connected to one conductor member, moreover, extend in the opposite transverse direction to thecorresponding dipole elements of the other conductor member (such as 5 to the left, 5' to the right; 7 to the left, 7' to the right; and so on).

The length of the dipole elements preferably successively increases from one end (11, 11' being the shortest) toward the other end (5, 5' being the longest), to provide directivity. For the VHF band, for example, conductors 1 and 1' may have a length of about 4% feet, with the dipole elements ranging from elements 5 about 4 /3 feet in length, to elements 11 about 2 /2 feet in length, and with the longitudinal separation between dipole elements ranging from about 1 /3 feet between elements 5 and 7, to slightly less than a foot between the front pairs of elements. The vertical separation of conductor members 1 and 1 may be of the order of 2", the longitudinal distance or spacing between the successive points of connection of successive pairs of dipoles being thus less than any wavelength in the VHF band and the vertical separation of the conductor members 1 and 1' being less than such longitudinal distance or spacing. Under such circumstances, excellent directivity is provided over the complete VHF band, as later illustrated.

A similar type of array II is connected to the front of the VHF antenna I and is used simultaneously not only as the feed structure for the VHF section I :but as the UHF directive antenna-receiving structure as well. That UHF structure II also employs a pair of longitudinal conductor members 1" and 1" which, in this case, in order to provide appropriate impedance to minimize interference by the structure II with the VHF performance of the structure I, is caused to be disposed in a manner diverging from a feedpoint; the left-hand portions of conductor members 1" and 1 being shown vertically extending upward and downward at A and A from the ends of conductor members 1 and 1', and then converging toward terminal feedpoint portions B and B to which a parallel wire transmission line TL is connected beyond an insulating clamp 2, securing the members 1" and 1 in spaced-apart relation. The line TL is shown supported below the antenna by a depending guide 2' associated with clamp 2 and a further guide 4 that may be supported by the conductor member 1. The dipole elements 5", 7 11" transversely extend from conductor member 1 in opposite directions to the directions of transverse extension from conductor member 1 of the corresponding dipole elements 7" 11", though such extension is at substantially right angles to the direction of conductor members 1" and 1" as distinguished from the acute angle extension on of the VHF dipole elements from conductor members 1 and 1'. The capacitance effect of the converging conductor members 1" and 1" together with the inductance of the sections A and A has been found to enable the UHF directivity reception antenna II to serve not only as transmission line connection means for the rightand end of the VHF antenna I, with minimal disturbing effect upon the VHF reception pattern, but to serve as an effective UHF receiving antenna as well. Further to that end, a stub termination 3 may be provided at the lefthand end of the conductor members 1 and 1'.

The lengths of the dipole elements 5", 7" 11" and 5", 7" 11" of the UHF antenna section II are caused to be successively shorter toward the convergent ends B and B for directivity considerations, as before discussed. As an example, the conductor members 1" and 1" may be about 13 inches long, the sections A and A about 3 inches long, the elements 5" and 5" about 7 inches long, the elements 11" and 11", forward of the insulating clamp 2, about 2 inches long, the separation between dipole elements ranging from about 2 inches to about 1% inches, and with the separation of the conductor members 1" and 1" ranging from about 9 inches to about an inch.

In addition to the support provided by the insulating clamp 2, the conductor members 1 and 1' may be rigidly maintained in mechanically spaced-apart relation by further insulating separators or clamps 20 and 21, the former of which may be associated with a clamp 22 for mounting the antenna upon a mast at a region remote from the free or right-hand end of the combined antenna structure I-H.

For substantially the dimensions above given, the UHF structure II has been found to produce a directive approximately SS-degree beam of from 5.5 to 6 db gain over the 478-890 mc. UHF .band; and, for the VHF section I, a 1 to 3.5 db gain 65-degree beam over the low VHF band of 54-88 mc. (operating as a half-wave system), and a 4 to 7.5 db gain 304legree directive beam in the high VHF band of 174-216 mc. (operating with a 3/2 wavelength response).

Modifications will occur to those skilled in this art and all such are considered to fall within the spirit and scope of the invention as defined in the appended claims.

What is claimed is:

1. An antenna for operation over a predetermined frequency band, having, in combination, a pair of rigid longitudinal conductor members held spaced apart in a vertical plane, first and second pluralities of dipole elements lying in corresponding first and second vertically spaced horizontal planes containing the respective conductor members, the dipole elements extending from opposite sides of and transversely to each conductor member at successive points therealong with dipole elements connected to one conductor member extending in opposite direction to the corresponding dipole elements of the other conductor member, the length of the dipole elements successively increasing from one end of the conductor members toward the other end thereof, means for connecting a parallel-wire transmission line to the said one end of the conductor members and comprising a further pair of longitudinal conductor members connected to the said one end and converging in the longitudinal direction away from said one end, rigid insulating means securing the said further pair of conductor members mechanically in spaced-apart relation and connected with means for supporting the transmission line near the convergent end thereof, and means for mounting the antenna at a region of the said conductor members remote from the said convergent end, further rigid insulating means being productor members mechanically in rigid spaced-apart relation near the said region.

2. An antenna as claimed in claim 1 and in which the first-mentioned conductor members are spaced apart a predetermined vertical distance less than the distances between the said successive points along the first-mentioned pair of conductor members and less than the wavelengths of the said band.

3. An antenna for operation over a predetermined frequency band, having, in combination, a pair of rigid longitudinal conductor members spaced apart in a vertical plane, first and second pluralities of dipole elements extending substantially horizontally from opposite sides of and transversely to each conductor member at successive points therealong with dipole elements connected to one conductor member extending in opposite direction to the corresponding dipole elements of the other conductor member, the length of the dipole elements successively increasing from one of the conductor members toward the other end thereof, means for connecting a parallelwire transmission line to the said one end of the conductor members, said connecting means comprising a further corresponding pair of longitudinally extending conductor members connected to the said one end and converging in the longitudinal direction away from the said one end, the further pair of conductor members each being provided with dipole elements extending transversely from opposite sides thereof at successive points therealong with the length of their respective dipole elements successively increasing in the direction toward the said first-named pair of longitudinal conductor members, rigid insulating means securing the said converging pair of conductor members mechanically in spaced-apart relation and connected with means for supporting the transmission line near the convergent end of the converging pair of conductor members, and means for mounting the antenna at a region of the said first-named pair of longitudinal conductor members remote from the said convergent end, further rigid insulating means being provided for securing the said firstnamed pair of longitudinal conductor members mechanically in rigid spaced-apart relation near the said region.

4. An antenna as claimed in claim 3 and in which the first-mentioned conductor members are spaced apart a predetermined vertical distance less than the distances between the said successive points along the first-named pair of longitudinal conductor members and less than the wavelengths of the said band.

5. An antenna as claimed in claim 3 and in which dipole elements of the said first-named pair of longitudinal conductor members are tuned within the VHF band and dipole elements of the pair of converging conductor members are tuned within the UHF band.

6. An antenna as claimed in claim 3 and in which the connection between the said first-named pair of longitudinal conductor members and the pair of converging conductor members comprises inductive conductor sections extending upward and downward from the respective conductor members of the first-named pair of longitudinal conductor members at the said one end.

7. An antenna as claimed in claim 3 and in which each of the dipole elements of the first-named pair of longitudinal conductor members extends transversely therefrom at an acute angle and each of the dipole elements of the pair of converging conductor members extends transversely therefrom at substantially right angles.

8. An antenna for operation over a predetermined wavelength band having, in combination, a pair of spaced longitudinally extending conductor members converging toward one end thereof, means for connecting a parallelwire transmission line near the said one end, each conductor member being provided with a plurality of dipole elements extending transversely from opposite sides thereof at successive points therealong and with the length of their respective dipole elements successively increasing in the direction toward the other end of the pair of conductor members, the said conductor members being provided with inductive conductor sections extending upward and downward from the respective conductor mnembcrs at the said other end thereof.

9. An antenna as claimed in claim 8 and in which there is provided rigid insulating means securing the said pair of conductor members mechanically in spaced-apart relation and connected with means for supporting the transmission line near the said one end.

10. An antenna as claimed in claim 8 and in which the said diploe elements extend transversely at substantially right angles to the respective conductor members.

11. An antenna as claimed in claim 8 and in which the spacing between the convergent ends of said conductor members is less than the longitudinal distances between said successive points and less than the wavelengths of said band.

12. An antenna for operation over a frequency band from about 54 megacycles to about 900 megacycles and including VHF and UHF sections, the VHF section comprising a pair of rigid longitudinal conductor members spaced apart in a vertical plane and provided with first and second pluralities of dipole elements extending substantially horizontally from opposite sides of and transversely to said conductor members, respectively, at successive points therealong with dipole elements connected to one conductor member extending in opposite direction t the corresponding dipole elements connected to the other conductor member, said dipole elements having a predetermined length-spacing distribution with the lengths of the dipole elements successively increasing from one end of the conductor members toward the other end thereof, said UHF section comprising a further pair of longitudinal conductor members connected to the said one end of the first-mentioned pair and converging away from said one end, the further pair of conductor members each being provided with dipole elements extending transversely from opposite sides thereof at successive points therealong and having a predetermined length-spacing distribution different from the first-mentioned distribution, the lengths of the dipoleelements extending from the further pair of conductor members successively increasing in the direction toward the said first-mentioned pair of conductor members, and means for connecting a transmission line to the convergent end of the further pair of conductor members, whereby said further pair of conductor members serves to feed both the UHF antenna section and the VHF antenna section.

13. An antenna in accordance with claim 12, further comprising means for mounting the antenna at a region intermediate the remote extremities of the VHF and UHF longitudinal conductor members considered together.

References Cited UNITED STATES PATENTS 3,150,376 9/1964 Carrel et a1. 343-7925 3,259,904 7/1966 Blonder et a1 343-7925 3,271,774 9/1966 Justice 343-7925 3,274,605 9/1966 Rauch 343-7925 ELI LIEBERMAN, Primary Examiner US. Cl. X.R. 

